JP6246034B2 - Method and apparatus for producing gallate oxide crystals - Google Patents

Description

  The present invention relates to a method for producing a gallate oxide crystal, and more particularly, to a production method and a production apparatus capable of producing a high-quality single crystal with few crystal defects and little decrease in resistivity under a high temperature environment. .

  Conventionally, a temperature sensor capable of wireless communication has been developed and used for the purpose of measuring the temperature in a closed space in a high temperature environment such as a semiconductor device chamber or an electric furnace and feeding it back to a control device. Therefore, a wireless temperature sensor that accurately measures a temperature in a high temperature environment exceeding 400 ° C. is required.

  For the purpose of improving fuel consumption and the like, a combustion pressure sensor has been proposed in which a pressure detection device using a piezoelectric element as a pressure detection unit is attached to an internal combustion engine and the combustion pressure in the combustion chamber can be detected with high accuracy. Yes.

  As described above, as a temperature sensor or pressure sensor usable in a high temperature furnace exceeding 400 ° C. or in a use environment in a combustion chamber, for example, a gallate oxide crystal piezoelectric material such as langasite or langate is proposed. ing. However, in general, in the production of gallate oxide crystals, there are problems such that crystal defects are likely to occur and the resistivity is remarkably lowered in a high temperature environment.

  In order to solve these problems of the gallate oxide crystal, for example, in the proposal shown in Patent Document 1, the inside of the chamber is made an atmosphere of a mixed gas of an inert gas and oxygen during the extraction of the gallate oxide crystal. A single crystal is grown while preventing evaporation of Ga (gallium) gas from the material melt in the crucible, and after drawing out the gallate oxide crystal, the mole fraction of oxygen in the chamber is lowered to reduce the inert gas. It is said that a gallate oxide crystal having a small temperature dependency of resistivity can be obtained by storing in an atmosphere.

  In addition, the method for producing a gallate oxide crystal disclosed in Patent Document 2 has a shortage of oxygen in the crucible that becomes a substantially sealed space when passing through a hole provided in the lid of the crucible as the single crystal grows. In order to compensate for this, a method of supplying a mixed gas of an inert gas and oxygen from a dedicated supply hole is employed. This makes it possible to grow and cool a single crystal while maintaining the same gas atmosphere inside the crucible and inside the chamber, and a crystal free of impurities such as iridium inclusions derived from an iridium crucible is obtained. It is said.

  Further, in the method for producing a gallate oxide crystal shown in Patent Document 3, a chamber is divided into a pulling chamber and a crystal chamber, and a structure is formed in which the two chambers are connected via a gate valve. A method of separating the growing process and the cooling (or heat treatment) process is adopted. Thereby, a single crystal with few crystal defects is obtained.

Japanese Patent No. 5174456 (2nd page) JP-A-55-136200 (page 3-4, FIG. 1) Japanese Unexamined Patent Publication No. 04-108682 (page 4, FIG. 1)

As described in Patent Document 1, in the manufacture of gallate oxide crystals, the vicinity of the liquid surface of a single crystal material melt is exposed to an atmosphere of a mixed gas of an inert gas and oxygen to form Ga (gallium). ) Can be prevented from evaporating.
In addition, the pulled single crystal is cooled in an oxygen-free inert gas atmosphere to suppress crystal defects, and a single crystal having a low resistivity temperature dependency can be obtained. It is extremely important to make the transition from a mixed gas atmosphere of oxygen and oxygen to a gas atmosphere closer to oxygen-free as soon as possible.

  However, in the conventional example shown in Patent Document 1, a single crystal is grown in an atmosphere of a mixed gas of an inert gas and oxygen in a chamber as a gallate oxide crystal growth condition. In the cooling process, it is described that if a single crystal is held in an inert gas atmosphere with little oxygen, a gallate oxide crystal having a low temperature dependency of resistivity can be obtained. In order to realize these atmospheric conditions, The specific manufacturing method and manufacturing apparatus are not mentioned. Furthermore, as described above, after the growth of the crystal is completed, the atmosphere is replaced with an oxygen-free inert gas atmosphere. Therefore, the crystals that are sequentially pulled up during the growth are placed in an atmosphere of a mixed gas of an inert gas and oxygen. Continue to be exposed. This is not considered, and the effect of suppressing crystal defects cannot be obtained during this period.

  Moreover, in the conventional example shown in Patent Document 2, the inside of the chamber including the inside of the crucible is set to a predetermined gas atmosphere, and a tube for supplying a mixed gas of an inert gas and oxygen into the crucible in order to compensate for the oxygen shortage in the crucible. Although a manufacturing method for providing and growing a single crystal is shown, the pulled single crystal is maintained and cooled in a chamber that is an atmosphere of a mixed gas of inert gas and oxygen similar to that in the crucible. There is no description of a method for realizing the transition to a gas atmosphere closer to oxygen-free.

  Further, in the conventional example shown in Patent Document 3, a manufacturing method is shown in which a chamber is divided into a pulling chamber and a crystal chamber, thereby separating a gallate oxide crystal growth step and a cooling (or heat treatment) step. However, there is no description about a method for realizing the transition to a gas atmosphere closer to oxygen-free.

(Object of invention)
Accordingly, an object of the present invention is to solve the above-described problems, and a region in which a single crystal grows from a melt of a crystal material is drawn between an inert gas and oxygen in the chamber while the single crystal is drawn. A gallate in which a single crystal is grown from a melt of a material in a mixed gas atmosphere, and the grown crystal is sequentially transferred and held in a gas atmosphere containing less oxygen and containing an oxygen-free inert gas as a main component. An oxide crystal manufacturing method is to be realized, and an atmospheric condition that satisfies the growth conditions of a single crystal is formed in a chamber without the need for complicated equipment and operation, and this is stably maintained. Accordingly, it is an object of the present invention to provide a manufacturing method and a manufacturing apparatus capable of manufacturing a high-quality gallate oxide crystal that suppresses crystal defects and has little decrease in resistivity even under a high temperature environment.

The manufacturing method of the gallate oxide crystal in the present invention is as follows.
In the method for producing a gallate oxide crystal, a crucible filled with a gallate oxide crystal material is placed in a chamber, and the gallate oxide crystal is grown by drawing from a melt obtained by heating the crucible and melting the material. Supply a mixed gas of an inert gas and oxygen in the vicinity of the melt, supply an oxygen-free inert gas from a position away from the supply position of the mixed gas to the melt, and perform drawing. It is characterized by.

  Thus, in the extraction of the single crystal, the region where the single crystal grows from the melt of the crystal material grows the single crystal from the melt of the material in an atmosphere of a mixed gas of inert gas and oxygen, and the grown crystal Can be transferred to a gas atmosphere containing less oxygen and containing an oxygen-free inert gas as a main component, which suppresses crystal defects and reduces resistivity even in high-temperature environments. The manufacturing method of a gallate oxide crystal can be enabled.

  Further, the supply pressure of the oxygen-free inert gas is higher than the supply pressure of the mixed gas.

  As a result, the oxygen-free inert gas is supplied to the melt from a position away from the supply position of the mixed gas, and the pressure is set high. While maintaining from the upper part of the crystal toward the melt side, the flow of the mixed gas of the inert gas and oxygen can be guided to the melt side.

  Further, the gas in the chamber is exhausted from the side opposite to the supply position for supplying the oxygen-free inert gas with respect to the position where the crucible is arranged.

  As a result, a smooth flow from the supply of oxygen-free inert gas to exhaust can be formed and maintained so that it flows from the single crystal side to the melt side, and the flow of the mixed gas of inert gas and oxygen also melts. It can be led to the liquid side and exhausted.

The apparatus for producing gallate oxide crystals in the present invention is as follows.
In a crystal manufacturing apparatus that manufactures a gallate oxide crystal by drawing it from a melt in which the material of the gallate oxide crystal is melted, a mixed gas of an inert gas and oxygen is placed in the vicinity of the melt in the chamber. A first gas supply port for supplying, a second gas supply port for supplying an oxygen-free inert gas to a position away from the first gas supply port with respect to the position where the melt is disposed, It is characterized by providing.

  As a result, in the extraction of the single crystal, the region where the single crystal grows from the melt of the crystal material grows the single crystal from the melt of the material in an atmosphere of a mixed gas of inert gas and oxygen, and the grown crystal Can be transferred to a gas atmosphere containing less oxygen and containing an oxygen-free inert gas as a main component, which suppresses crystal defects and reduces resistivity even in high-temperature environments. A production apparatus capable of producing a gallate oxide crystal can be provided.

  In addition, an exhaust port for exhausting air from the chamber is provided on the side opposite to the second gas supply port with respect to the position where the melt is disposed. As a result, the flow of the two gases can be stably maintained with a simple structure.

  The chamber divides the space between the crystal growth chamber in which the melt is placed and the crystal holding chamber, and between the crystal growing chamber and the crystal holding chamber, the crystal drawn from the crystal growing chamber holds the crystal. A partition member provided with an opening that can pass through the chamber, wherein the first gas supply port is provided in the crystal growth chamber and the second gas supply port is provided in the crystal holding chamber. Features.

  As a result, the partition member divides the chamber into a crystal growth chamber and a crystal holding chamber, and a mixed gas supplied from the first gas supply port and an oxygen-free inert gas supplied from the second gas supply port. Since the separability with gas can be improved, the composition change in the flow process of each gas can be suppressed.

Further, the first gas supply port is provided on the inner wall of the crystal growth chamber. Thereby, a 1st gas supply port can be provided in the appropriate position of the inner wall by the side of the crystal growth chamber formed of the partition member.

  The crystal growth chamber has a guide member provided with an opening through which the drawn crystal can pass, and a first gas supply port is provided on the inner wall of the chamber surrounded by the partition member and the guide member, And a gas supply path for introducing the mixed gas. Thereby, since the separability between the mixed gas of the inert gas and oxygen and the exhaust gas can be improved, the composition change in the flow process of each gas can be suppressed.

As described above, according to the present invention, a mixed gas of an inert gas and oxygen is supplied in the vicinity of the melt, and the oxygen-free inert gas is supplied to the melt from a position away from the supply position of the mixed gas. By supplying and pulling out the crystal, the region where the single crystal grows from the melt of the crystal material is grown and grown from the melt of the material in an atmosphere of a mixed gas of inert gas and oxygen. The crystals can be sequentially transferred and held in a gas atmosphere containing less oxygen and containing an oxygen-free inert gas as a main component.
As a result, it is possible to provide a method and an apparatus for producing a high-quality gallate oxide crystal with a simple structure, which suppresses crystal defects and causes little decrease in resistivity even under a high temperature environment.

1 is a schematic configuration diagram of an apparatus for producing a gallate oxide crystal for explaining Example 1. FIG. It is process drawing explaining the growth process and operation | movement of an oxide crystal by the manufacturing apparatus of FIG. It is a schematic block diagram of the manufacturing apparatus by Example 2. FIG. 6 is a schematic configuration diagram of a manufacturing apparatus according to a modified example of Embodiment 2. FIG.

  Hereinafter, the present invention will be described in detail with reference to the drawings. However, the embodiment described below exemplifies a manufacturing method and a manufacturing apparatus capable of manufacturing a gallate oxide crystal for embodying the idea of the present invention, and the present invention is a method described below. And it is not specific to the configuration. In particular, the materials, shapes, relative arrangements, and the like of the constituent members described in the embodiments are merely illustrative examples, and are not intended to limit the scope of the present invention unless otherwise specified. In addition, the size and positional relationship of the members shown in each drawing may be exaggerated for easy understanding.

  In the method and apparatus for producing a gallate oxide crystal of the present invention, in the extraction of a single crystal in a chamber, the region where the single crystal grows from the melt of the crystal material is in an atmosphere of a mixed gas of an inert gas and oxygen. A single crystal is grown in this order, and the grown crystal is successively transferred to an oxygen-free gas atmosphere containing an oxygen-free inert gas as a main component to suppress crystal defects, even in a high-temperature environment. This makes it possible to produce high-quality gallate oxide crystals with little decrease in resistivity.

In order to realize such a crystal growth condition, a first gas supply port for supplying a mixed gas of an inert gas and oxygen in the vicinity of the melt is disposed in the chamber, and the melt is disposed. And a second gas supply port for supplying an oxygen-free inert gas at a position away from the first gas supply port in the crystal drawing direction with respect to the formed position. The supply pressure of the oxygen-free inert gas is set higher than the supply pressure.
In addition, a partition member is provided in the chamber to divide the space into a crystal growth chamber and a crystal holding chamber in which the melt is disposed, the first gas supply port is on the crystal growth chamber side, and the second gas supply port is on the crystal By disposing on the holding chamber side, it is possible to further optimize the respective gas atmospheres of the crystal growth and holding environment, thereby improving the crystal quality after the growth.

First, Example 1 will be described with reference to FIGS. 1 to 2, and then Example 2 will be described with reference to FIGS. 3 to 4. In Example 1, a configuration example of a manufacturing apparatus and a gallate oxide crystal growth process and operation using the apparatus will be described.
Further, in Example 2, in order to further improve the respective gas atmospheres of the crystal growth and holding environment, a configuration example provided with a partition member that divides the chamber into a crystal growth chamber and a crystal holding chamber, and this configuration example Further, a configuration in which a guide member is further provided will be described as a modification of the second embodiment.

[Description of Example 1: FIGS. 1-2]
FIG. 1 is a cross-sectional view of the gallate oxide crystal manufacturing apparatus 100 according to the first embodiment in the direction of the central axis CL. FIG. 2 shows a single crystal manufacturing process divided into four stages in the manufacturing apparatus 100 shown in FIG. FIG. 6 is a cross-sectional view in the direction of the central axis CL showing the operation in each step.

[Description of Configuration of First Embodiment: FIG. 1]
First, FIG. 1 shows an oxide crystal manufacturing apparatus 100 based on a known Czochralski method, and shows a cross-sectional view of a chamber 40 (container part) which is a component thereof. Here, the crystal pulling control device, the crucible heater, the gas supply device, the gas supply pipe, the gas exhaust pipe, the pressure adjusting device, etc., which are other components of the oxide crystal manufacturing apparatus 100, are omitted. Only elements related to crystal growth, such as the chamber 40, the crucible 8, the material melt 50, the seed crystal 65, and the crystal drawing rod 6 according to the present invention are shown.

  In FIG. 1, a chamber 40 includes a cylindrical member 1, a lid member 2 fixed to the upper part of the cylindrical member 1, and a base member 3 fixed to the lower part of the cylindrical member 1. It is an airtight container.

  Next, the cylindrical member 1 constituting the chamber 40 has a cylindrical shape, and a crucible 8 containing a crystal material melt 50 to be described later can be arranged in the center of the inner space. A first gas supply port 11 for supplying a mixed gas 70 of inert gas and oxygen is provided on the inner wall portion of the cylindrical member 1 located in the vicinity of the upper portion of the crucible 8, and two gas supply ports 11 are arranged on both sides. The two first gas supply ports 11 are preferably arranged at positions that are point-symmetric with respect to the central axis CL (see FIG. 1) of the cylindrical member 1, and are uniformly supplied toward the central axis CL. It can be done. Here, the number of the first gas supply ports 11 may be further increased so that the first gas supply ports 11 are arranged at equal intervals on the circumference with respect to the central axis CL of the cylindrical member 1.

  Next, the lid member 2 constituting the chamber 40 has a disc shape, and has a cylindrical convex portion 20 at the center. Further, a shaft hole 22 serving as a rotation center (center axis CL) of the crystal operation rod 6 described later is provided on the upper surface portion of the cylindrical convex portion 20. In addition, a second gas supply port 21 for supplying the oxygen-free inert gas 80 is provided in the cylindrical portion of the cylindrical convex portion 20 in one direction perpendicular to the cylindrical portion. When the oxygen-free inert gas 80 is supplied from the second gas supply port 21 to the inner wall side of the cylindrical projection 20, the direction changes from there and toward the lower inside of the cylindrical member 1, the central axis CL Is supplied uniformly on the basis of the above. Here, in order to supply the oxygen-free inert gas 80 more uniformly in the direction of the crucible 8 with respect to the central axis CL, the position of the second gas supply port 21 is set on the upper surface portion. It may be changed, or may be provided on the inner wall portion of the cylindrical member 1 and closer to the lid member 2 than the first gas supply port 11. Further, the number of supply ports may be increased.

Next, the pedestal member 3 constituting the chamber 40 has a disk shape, and the upper surface side has a flat region so that the crucible 8 can be disposed. In addition, the lower surface side has a foot 30 around it so that the chamber 40 can be stabilized.
Two exhaust ports 31 are provided on both sides between the outer periphery of the crucible 8 of the pedestal member 3 and the inner periphery of the cylindrical member 1, and exhaust 90 (a mixed gas 70 of inert gas and oxygen and oxygen-free oxygen). The inert gas 80) can be discharged. The exhaust port 31 is located on the opposite side to the side where the second gas supply port 21 (the supply port of the oxygen-free inert gas 80) is disposed, that is, the crystal, relative to the position where the crucible 8 is disposed. It is arrange | positioned so that it may become the opposite side with respect to the pulling-up direction.
Here, the flow of the mixed gas 70 of the inert gas and oxygen supplied from the first gas supply port 11 and the flow of the oxygen-free inert gas 80 supplied from the second gas supply port 21 are described above. In order to improve the uniformity, the number of the exhaust ports 31 may be increased, and the position of the exhaust ports 31 may be changed. The position, quantity, and hole diameter of the exhaust port 31 may be adjustable.

Next, the crystal pulling rod 6 and the seed crystal 65 for pulling out the single crystal 60 will be described. The crystal drawing rod 6 has a crystal holding member 7 for holding the seed crystal 65 on the tip side (the crucible 8 side). Further, the rear end side of the crystal pulling bar 6 is coupled to a shaft hole 22 formed in the upper part of the cylindrical convex portion 20 of the lid member 2 so as to be rotatable and vertically movable. In addition, a crystal drawing control device that performs rotation and vertical movement (not shown) can rotate under predetermined conditions and can move up and down under predetermined conditions.
The seed crystal 65 is a bulk crystal having the same composition as that of the single crystal 60 and is held by the crystal holding member 7 so as to grow along a predetermined crystal orientation. The shape of the seed crystal 65 is exclusively a rectangular parallelepiped (square prism) shape, and a predetermined surface is brought into contact with the material melt 50 described later, but the seed crystal 65 is processed and contacted with the material melt 50 as shown in FIG. By making the side to be sharpened into a pointed shape, it is possible to suppress the occurrence of dislocation due to a sudden thermal shock when contacting the material melt 50.

Next, the crucible 8 and the material melt 50 will be described. The crucible 8 is a cylindrical container made of, for example, Ir (iridium), and can be filled with the material melt 50 therein. The crucible 8 is arranged so that the center of the cylindrical portion thereof substantially coincides with the rotation center of the crystal pulling rod 6 described above.
The material melt 50 contains a mixture of powders of each component of the gallate oxide crystal to be produced in a predetermined composition ratio inside the crucible 8 and heats the crucible with a heater (not shown). The powder material is melted at a predetermined temperature.
Note that the crucible 8 has a volume that can be filled with the required amount of material melt 50 determined by calculating the size of the single crystal to be produced, for example. In addition, although conditions, such as a composition ratio of the oxide powder which is each material, and heating temperature, change with crystals to grow, description is abbreviate | omitted for details here.

In the above configuration, the supply pressure of the mixed gas 70 of inert gas and oxygen and the supply pressure of the oxygen-free inert gas 80 are controlled to predetermined values through a gas supply pipe by a pressure supply device (not shown). Supply from the supply port. The oxygen-free inert gas 80 is supplied from the upper side to the lower side of the chamber 40, and an atmosphere having an extremely low oxygen concentration is formed above the first gas supply port 11. Further, since the oxygen-free inert gas 80 has a higher pressure than the mixed gas 70 of inert gas and oxygen, the mixed gas 70 of inert gas and oxygen is pushed down, and the first gas supply port 11 is pressed. Is prevented from diffusing upward. In particular, due to the oxygen-free inert gas 80 flowing in the vicinity of the central axis CL, the supply direction of the mixed gas 70 of the inert gas and oxygen is caused by the oxygen-free inert gas 80 having a high pressure near the central axis CL. It is bent in the direction of the material melt 50. As a result, the mixed gas 70 of the inert gas and oxygen can cover the vicinity of the surface of the material melt 50, thereby preventing Ga evaporation, and thus preventing variation in the composition ratio of the material melt 50. That is, there is a difference in oxygen concentration along the central axis CL of the single crystal in the chamber 40, the oxygen concentration is high in the vicinity of the material melt 50, and the oxygen concentration decreases in the growth direction.
In particular, the space from the position parallel to the first gas supply port 11 to the second gas supply port 21 is preferably an oxygen-free gas atmosphere in order to hold the grown single crystal. Thus, it is preferable to control a pressure adjusting device (not shown).

  The mixed gas 70 of inert gas and oxygen and the oxygen-free inert gas 80 flow to the outside of the crucible 8 and are exhausted from the exhaust port 31 as exhaust 90. The amount of exhaust from the exhaust port 31 is controlled by, for example, a vacuum pump (not shown), whereby the mixed gas 70 of inert gas and oxygen diffuses upward from the first gas supply port 11. It can be suppressed more.

  The flow state of the two gases as described above is stably maintained, the crystal pulling rod 6 holding the seed crystal 65 is lowered, and the seed crystal 65 is immersed in the material melt 50. Next, the single crystal 60 is pulled out from the crystal drawing rod 6 under a predetermined rotation condition and a predetermined pulling condition. Thereby, the growth of the single crystal 60 can be started.

The main gallate oxide single crystals to be manufactured by applying the manufacturing method and manufacturing apparatus of gallate oxide crystals according to the present invention are, for example, LGS (La ₃ Ga _5.5 Si _0.5 O ₁₄ ), LTG (La ₃ Ga). _5.5 Ta _0.5 O ₁₄ ), LTGA (La ₃ Ga _5.5-x Ta _0.5 Al _x O ₁₄ (0 <x <5.5).

[Description of Operation in Each Manufacturing Process of Example 1: FIG. 2]
Next, the operation | movement in each manufacturing process of a gallate oxide crystal is demonstrated using FIG. FIG. 2 shows the manufacturing process of the single crystal 60 in four stages. As the single crystal 60 is grown, (a) an initial stage of growth, (b) an intermediate stage of growth, (c) an end stage of growth, (d ) It will be described as a holding stage. In order to describe the gas flow (operation) in the chamber 40, the mixed gas 70 of the inert gas and oxygen is indicated by a broken line arrow, and the oxygen-free inert gas 80 is indicated by a solid line arrow. An exhaust gas 90 composed of a mixed gas 70 of inert gas and oxygen and an oxygen-free inert gas 80 is indicated by a dotted arrow.

[Initial growth stage: FIGS. 1 and 2 (a)]
First, FIG. 2 (a) shows the state of the initial stage of growth in pulling out the single crystal 60. As described with reference to FIG. 1, the structure of this embodiment is lowered and the crystal pulling rod 6 holding the seed crystal 65 is lowered. The seed crystal 65 is immersed in the material melt 50, and the single crystal 60 is pulled out under a predetermined rotation condition and a predetermined pulling condition, and the single crystal 60 has a predetermined outer diameter. At this time, the mixed gas 70 of the inert gas and oxygen is uniformly supplied from the first gas supply port 11 (FIG. 1) provided in the cylindrical member 1 toward the central axis CL of the chamber, and the single crystal 60. Reach near the top. On the other hand, the oxygen-free inert gas 80 is supplied from the second gas supply port 21 (FIG. 1) provided in the lid member 2 and is uniformly directed downward with the crystal drawing rod 6 (FIG. 1) as the center. Supplied.

At this time, the mixed gas 70 of the inert gas and oxygen is supplied from the first gas supply port 11 by the oxygen-free inert gas 80 whose gas pressure is higher than that of the mixed gas 70 of the inert gas and oxygen. Is also prevented from diffusing upward, that is, in the direction of the second gas supply port 21. In particular, the mixed gas 70 of inert gas and oxygen supplied from a certain first gas supply port 11 is near the upper portion of the single crystal 60 (in the vicinity of the central axis CL). The gas melt collides with the mixed gas 70 and the crystal 60 of the inert gas and oxygen supplied from above, but the upward diffusion is suppressed by the oxygen-free inert gas 80 existing in the vicinity thereof, so that the material melt It is pushed down to the 50 side and supplied to the liquid surface of the material melt 50.
On the other hand, the oxygen-free inert gas 80 covers the vicinity of the upper surface of the single crystal 60, and a part of the exhaust gas is provided with the mixed gas 70 of the inert gas and oxygen and an exhaust port provided in the base member 3 (FIG. 1). 31 (FIG. 1) is exhausted as exhaust 90.

Thus, in the initial stage of growth, the liquid surface of the material melt 50 filled in the crucible 8 is covered with the mixed gas 70 of the inert gas and oxygen to prevent Ga evaporation. On the other hand, near the upper surface of the single crystal 60 in the initial stage of growth and above it, it is covered with an oxygen-free inert gas 80. That is, in the extraction of the single crystal 60, the region where the single crystal 60 grows from the material melt 50 is in the atmosphere of the mixed gas 70 of inert gas and oxygen, and the grown crystals are successively oxygen-free inert. The gas can be transferred into a gas atmosphere containing the gas 80 as a main component and containing less oxygen.
As described above, the mixed gas 70 of the inert gas and oxygen partially mixes with the oxygen-free inert gas 80 in the vicinity of the material melt 50, so that the Ga component is evaporated in anticipation of mixing in advance. It is preferable to set the molar concentration of oxygen so as to obtain an optimum value for preventing the above. If the conditions for obtaining a predetermined gas atmosphere are satisfied, only oxygen is supplied from the first gas supply port 11 and mixed with the oxygen-free inert gas 80 supplied from the second gas supply port 21. However, it may be controlled so as to have a predetermined oxygen molar concentration in the vicinity of the material melt 50.

[Growth stage: Fig. 2 (b)]
Next, FIG. 2B shows a state in the middle of growth in the drawing of the single crystal 60, where the single crystal 60 maintains a predetermined outer diameter and the growth has progressed. At this time, the mixed gas 70 of the inert gas and oxygen maintains the state of the step (a) described above, and the mixed gas 70 of the inert gas and oxygen is an oxygen-free inert gas in the vicinity of the single crystal 60. 80 is pushed down to the material melt 50 side and supplied to the surface of the material melt 50. On the other hand, the oxygen-free inert gas 80 in the vicinity of the single crystal 60 covers the surface of the grown single crystal 60 from above toward the liquid surface of the material melt 50, and then a mixed gas of inert gas and oxygen. 70 is exhausted from the exhaust port 31 as exhaust 90.
Thereby, since the grown single crystal 60 is suppressed from being exposed to oxygen, it is possible to prevent a crystal defect caused by oxygen from occurring.

  In this way, even in the middle of the growth, the region where the single crystal 60 grows from the crystal material melt 50 in the extraction of the single crystal 60 is in the atmosphere of the mixed gas 70 of inert gas and oxygen, and is grown. The resulting crystals are sequentially transferred into a gas atmosphere containing less oxygen and containing oxygen-free inert gas 80 as a main component.

[Growth termination stage: FIG. 2 (c)]
Next, FIG. 2 (c) shows a state at the end of growth in pulling out the single crystal 60, and is a state in which the single crystal 60 has been thinned in a conical shape from a predetermined outer diameter and crystallization has ended. At this time, the mixed gas 70 of the inert gas and oxygen enters the space formed between the material melt 50 and the single crystal 60 from the state of step (b) described above, and the liquid level of the material melt 50 And the entire material melt 50 can be covered. On the other hand, the oxygen-free inert gas 80 in the vicinity of the single crystal 60 covers the surface of the single crystal 60 from the upper part to the lower part, and then as the exhaust gas 90 from the exhaust port 31 together with the mixed gas 70 of the inert gas and oxygen. Exhausted.
Here, by adjusting, for example, increasing the pressure of the oxygen-free inert gas 80, an atmosphere in which the single crystal 60 is not exposed to oxygen can be formed. It can be transferred to an atmosphere containing less oxygen as a main component.

  Thus, even in the growth end stage, after the drawing of the single crystal 60 is finished, the liquid surface of the material melt 50 is in the atmosphere of the mixed gas 70 of the inert gas and oxygen. Almost the whole has been transferred to a gas atmosphere containing less oxygen and mainly composed of an oxygen-free inert gas 80.

[Holding stage held in holding chamber: FIG. 2 (d)]
Next, FIG. 2 (d) shows a state of a holding stage for holding the single crystal 60, in which the single crystal 60 has a predetermined shape and crystal growth is completed and held in the upper portion of the chamber 40. At this time, the mixed gas 70 of the inert gas and oxygen wraps around the space formed between the material melt 50 and the single crystal 60 in the same manner as in the step (c) described above, and the liquid of the material melt 50 is obtained. It is supplied to the surface and covers the whole. On the other hand, the oxygen-free and oxygen-free inert gas 80 in the vicinity of the single crystal 60 covers the entire surface of the single crystal 60 from the top to the bottom, and then exhausts together with the mixed gas 70 of the inert gas and oxygen. Exhaust gas 90 is exhausted from the port 31.

  Here, after the pulling out of the single crystal 60 is completed in the above-described growth end stage or the holding stage held in the holding chamber, the heating process of the crucible 8 by a heater (not shown) is stopped, and thereby the Ga from the material melt 50 is stopped. As the amount of evaporation decreases, the supply amount of the mixed gas 70 of inert gas and oxygen is reduced, and finally, the supply is stopped, so that the entire chamber 40 has a gas atmosphere with less oxygen. It's still better.

As described above, in the holding stage of holding in the holding chamber, the transition of the single crystal 60 to the atmosphere of the oxygen-free inert gas 80 is completed.
Note that the single crystal 60 may be subjected to subsequent steps such as cooling or heat treatment in a state where the single crystal 60 is maintained in an oxygen-free atmosphere as necessary.

[Effect of Example 1]
According to the present embodiment described above, the following effects can be obtained.
[Effect 1]
In the chamber 40, the first gas supply port 11 for supplying the mixed gas 70 of the inert gas and oxygen in the vicinity where the material melt 50 is disposed, and the position where the material melt 50 is disposed, A second gas supply port 21 for supplying an oxygen-free inert gas 80 is provided at a position away from the first gas supply port 11 in the crystal drawing direction. Since the supply pressure of the oxygen-free inert gas 80 is higher than the supply pressure of the mixed gas 70, the region where the single crystal 60 grows from the material melt 50 in the extraction of the single crystal 60 is inert gas and oxygen. The single crystals 60 grown in the atmosphere of the mixed gas 70 can be sequentially transferred into a gas atmosphere containing less oxygen and containing oxygen-free inert gas 80 as a main component.
In addition, since the produced single crystal 60 can be maintained as it is in the atmosphere of the oxygen-free inert gas 80, high-quality gallate oxidation is suppressed without causing crystal defects and having little decrease in resistivity even in a high-temperature environment. A manufacturing method and a manufacturing apparatus capable of manufacturing a physical crystal can be provided.
[Effect 2]
Further, since only a supply pressure of at least two kinds of gases (an oxygen-free inert gas and an oxygen-containing inert gas) is controlled without requiring a complicated device, the single crystal 60 is formed in the chamber 40. Atmospheric conditions that satisfy the growing conditions can be easily formed, and can be stably maintained. Further, since no switching operation such as gas replacement is required for the single crystal 60, it is possible to suppress crystal defects caused by continuing exposure to oxygen before switching.

The distance between the first gas supply port 11 and the material melt 50 accommodated in the crucible 8, the diameter and depth of the crucible 8, the volume of the material melt 50, etc. are not limited to this. The diameter and length of 60 may be appropriately changed according to the pressure difference between the two gases.
Other gallate oxide crystals that can be manufactured by applying the method and apparatus for manufacturing gallate oxide according to the present invention include, for example, gallium oxide (Ga ₂ O ₃ ), gadolinium gallium garnet (Gd ₃ Ga _5). O ₁₂ ), lithium gallate (LiGaO ₂ ), neodymium gallate (NdGaO ₃ ), yttrium gallium garnet (Y ₃ Ga ₅ O ₁₂ ), and the like.

As described above, in Example 1, the atmosphere for crystal growth and the atmosphere for holding the crystal are only controlled by the pressure control of the mixed gas of the inert gas and oxygen and the oxygen-free inert gas. The gas atmosphere was controlled.
Next, the configuration of Example 1 is further improved. Example 2 in which a partition member is provided in a part of the chamber to partially physically separate two gas atmospheres, and the first Two examples of the modified example of Example 2 provided with a guide member for efficiently guiding the mixed gas of the inert gas and oxygen supplied from the gas supply port in the central axis direction will be described in order.

[Description of Example 2: FIG. 3]
First, a schematic configuration of the gallate oxide crystal manufacturing apparatus 200 according to the second embodiment will be described with reference to FIGS. 3 (a) and 3 (b). The gallate oxide crystal manufacturing apparatus 200 according to the second embodiment is different from the above-described gallate oxide crystal manufacturing apparatus 100 according to the first embodiment in that a mixed gas 70 of inert gas and oxygen and an oxygen-free inert gas are used. The partition member 4 is provided in the chamber 40 for the purpose of improving the separability from the chamber 80, and the basic configuration is the same as that of the first embodiment. Are partially omitted.

  3A is a cross-sectional view of the gallate oxide crystal manufacturing apparatus 200 in the direction of the central axis CL, and FIG. 3B is a perspective view of the cross section of FIG. is there. In FIG. 3A, a gallate oxide crystal manufacturing apparatus 200 is provided with a supply port 11 for a mixed gas 70 of an inert gas and oxygen provided on the inner wall of a chamber 40 of the gallate oxide crystal manufacturing apparatus 100 described above. A partition member 4 is provided in the vicinity of the upper portion of the. Moreover, in FIG.3 (b), the partition member 4 has the circular opening 4a in the center part, and has shown that the external shape is a circular disk-shaped member. Further, the outer periphery of the partition member 4 and the inner wall of the cylindrical portion of the cylindrical member 1 constituting the chamber 40 are joined with no gap.

In FIG. 3A, the interior of the chamber 40 is divided by the partition member 4 into a crystal growth chamber 45 in which the crucible 8 is disposed and a crystal holding chamber 46 in which the drawn crystal is held. The supply port 11 for the mixed gas 70 of inert gas and oxygen is disposed in the crystal growth chamber 45, and the supply port 21 for the oxygen-free inert gas 80 is disposed in the crystal holding chamber 46.
The circular opening 4a provided in the central portion of the partition member 4 allows the single crystal 60 drawn from the material melt 50 in the crucible 8 to pass through, and at the same time, the second gas supply port 21. There is a gap so that the oxygen-free inert gas 80 supplied from the gas can flow from the crystal holding chamber 46 side to the crystal growing chamber 45 side.

  With the above structure, the mixed gas 70 of the inert gas and oxygen supplied from the first gas supply port 11 is converted to the oxygen-free inert gas 80 supplied from the second gas supply port 21 by the partition member 4. Therefore, the two gases can flow without mixing in the section from the first gas supply port 11 to the vicinity of the outer periphery of the single crystal 60. In the vicinity of the single crystal 60, the mixed gas 70 of the inert gas and oxygen is pushed down by the oxygen-free inert gas 80 and supplied to the liquid surface of the material melt 50. As a result, in the section from the first gas supply port 11 to the opening 4a of the partition member 4, the mixed gas 70 of the inert gas and oxygen in which the decrease in the molar concentration of oxygen (composition change) is suppressed is reduced to the material melt 50. Can be supplied to.

On the other hand, the oxygen-free inert gas 80 supplied from the second gas supply port 21 is separated from the inert gas and oxygen mixed gas 70 supplied from the first gas supply port 11 by the partition member 4. Therefore, since the pressure of the oxygen-free inert gas 80 is higher than that of the mixed gas 70 of the inert gas and oxygen, it can flow without mixing on the crystal holding chamber 46 side. Further, the section from when the oxygen-free inert gas 80 enters the crystal growth chamber 45 side and is mixed with the mixed gas 70 of the inert gas and oxygen can cover the outer periphery of the single crystal 60. Thereby, the single crystal 60 being drawn can be covered with the oxygen-free inert gas 80 (no composition change) on the crystal holding chamber 46 side, and further up to the middle of the single crystal 60 on the crystal growth chamber 45 side. Can be covered with an oxygen-free inert gas 80.

[Effect of Example 2]
According to the second embodiment of the present invention described above, the following effects can be obtained.
In the drawing of the single crystal 60, the partition member 4 is provided in the chamber 40 for the purpose of improving the separation between the mixed gas 70 of inert gas and oxygen and the oxygen-free inert gas 80. Since mixing can be delayed to the vicinity of the outer periphery of the single crystal 60, a change in composition during the flow of each gas can be suppressed. Thereby, the manufacturing method and manufacturing apparatus which can suppress the defect of a crystal | crystallization and can perform more stable manufacture of the high quality gallate oxide crystal | crystallization with little fall of a resistivity also in a high temperature environment can be provided.

  The distance between the partition member 4 and the first gas supply port 11, the size of the opening 4a of the partition member 4, the distance between the partition member 4 and the material melt 50, and the shape of the crucible (edge height, diameter) These are not limited, and may be appropriately changed according to the outer diameter and length of the single crystal 60 to be produced, the pressure difference between the two gases, the flow state, and the like. In consideration of the fluidity and separability of the two gases, the partition member 4 may be inclined from the inner wall side of the chamber 40 toward the single crystal side, whereby a mixed gas of an inert gas and oxygen. 70 can be efficiently supplied to the material melt 50, and the grown single crystal 60 can be transferred to a gas atmosphere containing no oxygen more quickly. Further, a cylindrical member may be provided from the opening 4 a of the partition member 4 toward the material melt 50. Thereby, since the mixed gas 70 of the inert gas and oxygen supplied from the first supply port 11 flows toward the material melt 50 by the cylindrical member, the oxygen-free inert gas 80 is different from the material. It is more preferable because it merges in the vicinity of the interface of the melt 50.

[Description of Modified Example of Embodiment 2: FIG. 4]
Next, a schematic configuration of a gallate oxide crystal manufacturing apparatus 300, which is a modification of the second embodiment, will be described with reference to FIGS. 4 (a) and 4 (b). The apparatus 300 for producing a gallate oxide crystal according to the present embodiment can efficiently lead a mixed gas 70 of an inert gas and oxygen to the material melt 50 with respect to the apparatus 200 for producing a gallate oxide crystal described above. In addition, for the purpose of improving the separation from the exhaust 90, the guide member 5 is provided below the partition member 4 provided in the chamber 40 with the first gas supply port 11 interposed therebetween. Since the configuration is the same as the configuration described above in the second embodiment, the same elements are denoted by the same reference numerals, and a part of overlapping description is omitted.

4A is a cross-sectional view of the gallate oxide crystal manufacturing apparatus 300 in the direction of the central axis CL, and FIG. 4B is a perspective view of the cross section of FIG. is there.
In FIG. 4A, the gallate oxide crystal production apparatus 300 is configured to supply an inert gas and oxygen to the partition member 4 provided on the inner wall of the chamber 40 of the gallate oxide crystal production apparatus 200 described above. A guide member 5 is provided on the lower side across the supply port 11 of the mixed gas 70. 4B, the guide member 5 is disposed below the partition member 4, has a circular opening 5a at the center, and indicates that the outer shape is a circular disk-shaped member. .

  In the space formed between the partition member 4 and the guide member 5, a gas supply path for guiding a mixed gas 70 of inert gas and oxygen supplied from the first gas supply port 11 is formed. The guide member 5 has the same shape (outer shape and opening) as that of the partition member 4, and the inner wall of the tubular portion of the tubular member 1 and the outer periphery of the guide member 5 are joined with no gap. Thereby, the mixed gas 70 of the inert gas and oxygen supplied from the 1st gas supply port 11 is supplied from the 2nd gas supply port 21 in the area from the 1st gas supply port 11 to the opening part 5a. The oxygen-free inert gas 80 is separated from the exhaust gas 90 and the exhaust gas 90 is further separated.

With the above structure, the mixed gas 70 of the inert gas and oxygen supplied from the first gas supply port 11 is an oxygen-free inert gas in the section from the first gas supply port 11 to the opening 5a. Mixing with 80 can be suppressed. Thereby, the mixed gas 70 of the inert gas and oxygen which suppressed further the fall of the molar concentration of oxygen can be supplied to the liquid level of the material melt 50.
[Effect of Modification of Example 2]
According to the modification of the second embodiment of the present invention described above, the following effects can be obtained.
A first gas supply path is formed in the chamber 40 by a structure in which the guide member 5 is provided below the partition member 4 with the first gas supply port 11 interposed therebetween, and is supplied from the first gas supply port 11. Therefore, it is possible to prevent the mixed gas 70 of inert gas and oxygen from immediately diffusing into the crystal growth chamber 45, so that the gas can be stably guided to the material melt 50. Further, since mixing with the oxygen-free inert gas 80 is suppressed, the mixed gas 70 of the inert gas and oxygen in which the decrease in the molar concentration of oxygen (composition change) is further suppressed is used as the liquid surface of the material melt 50. Can be supplied to. As a result, the action of preventing the evaporation of Ga gas from the material melt 50 in the crucible 8 is stabilized, and the production of high quality gallate oxide crystals with few crystal defects and little decrease in resistivity even in a high temperature environment is achieved. A possible manufacturing method and manufacturing apparatus can be provided.

  4A and 4B, the partition member 4 and the guide member 5 have been described as having substantially the same shape. However, the present invention is not limited to this, and the opening 5a of the guide member 5 is more than the opening 4a of the partition member 4. May be larger. For example, if the size is not less than the diameter of the crucible and not more than the opening 4 a of the partition member 4, the mixed gas 70 of inert gas and oxygen is supplied more uniformly because it diffuses from the opening 5 a in the crucible direction, that is, in the material melt 50. It can be convenient.

  Further, the distance between the guide member 5 and the material melt 50 (the height of the supply path), the size of the opening 5a, etc. are not limited, and the outer diameter and length of the single crystal 60 to be produced, the pressure difference between the two gases. It may be changed appropriately according to the flow situation. In consideration of fluidity and separation of the two gases, the gas supply path formed by the partition member 4 and the guide member 5 may be inclined from the inner wall of the chamber toward the single crystal side. Alternatively, either the partition member 4 or the guide member 5 may be inclined.

  Further, a cylindrical member may be provided from the opening 4 a of the partition member 4 toward the material melt 50. Thereby, since the mixed gas 70 of the inert gas and oxygen supplied from the first supply port 11 flows toward the material melt 50 by the cylindrical member, the oxygen-free inert gas 80 is different from the material. It is more preferable because it merges in the vicinity of the interface of the melt 50.

  As described above in each example, in the production of a gallate oxide crystal, a region where a single crystal grows from a melt of a crystal material is obtained from a material melt in an atmosphere of a mixed gas of an inert gas and oxygen. It is possible to provide a method and an apparatus for producing a gallate oxide crystal in which crystals are grown and the grown single crystals are sequentially transferred and held in an oxygen-free inert gas atmosphere.

DESCRIPTION OF SYMBOLS 1 Cylindrical member 2 Lid member 3 Base member 4 Partition member 5 Guide member 6 Crystal drawing rod 7 Crystal holding member 8 Crucible 11 1st gas supply port (supply port of mixed gas of an inert gas and oxygen)
21 Second gas supply port (oxygen-free inert gas supply port)
31 Exhaust port 40 Chamber 45 Crystal growth chamber 46 Crystal holding chamber 50 Material melt (melt of crystal material, melt)
60 Single crystal (gallate oxide crystal, crystal)
65 Seed crystal 70 Mixed gas of inert gas and oxygen 80 Oxygen-free inert gas 90 Exhaust gas 100, 200, 300 Crystal production apparatus for gallate oxide crystal

Claims (7)

Place a crucible filled with gallate oxide crystal material in the chamber,
In the method for producing a gallate oxide crystal, the gallate oxide crystal is grown by heating the crucible and drawing it from a melt obtained by melting the material.
In the vicinity of the melt, a mixed gas of an inert gas and oxygen is supplied,
An oxygen-free inert gas is supplied to the melt from a position away from the supply position of the mixed gas,
The supply pressure of the oxygen-free inert gas is higher than the supply pressure of the mixed gas,
A method for producing a gallate oxide crystal, wherein the molten gas surface is covered with the mixed gas by pushing down the mixed gas to the molten liquid side with the oxygen-free inert gas, and the drawing is performed. Relative position where the crucible is disposed, from the opposite side to the supply position for supplying the inert gas in the oxygen-free, according to claim 1, characterized in that the exhaust gas in the chamber A method for producing a gallate oxide crystal. In a crystal production apparatus for producing a gallate oxide crystal by drawing from a melt in which the material of the gallate oxide crystal is melted,
A first gas supply port for supplying a mixed gas of an inert gas and oxygen in the vicinity of the melt disposed in the chamber;
Relative position where the melt is disposed, at a position apart from the first gas supply port, and a second gas supply port for supplying the oxygen-free inert gas,
The supply pressure of the oxygen-free inert gas can be set higher than the mixed gas,
An apparatus for producing a crystal of a gallate oxide crystal, wherein the molten liquid surface is covered with the mixed gas by pushing the mixed gas down to the molten liquid side with the oxygen-free inert gas . The gallate oxidation according to claim 3 , further comprising an exhaust port for exhausting from the inside of the chamber on a side opposite to the second gas supply port with respect to a position where the melt is disposed. Crystal manufacturing equipment for physical crystals. The chamber divides the space into a crystal growth chamber in which the melt is disposed and a crystal holding chamber, and a crystal drawn from the crystal growth chamber is between the crystal growth chamber and the crystal holding chamber. A partition member provided with an opening that can pass through the crystal holding chamber,
The first gas supply port is provided in said crystal growth chamber, the second gas supply port gallate oxide according to claim 3 or 4, characterized in that provided in the crystal holding chamber Crystal manufacturing equipment for physical crystals. The apparatus for producing a gallate oxide crystal according to claim 5 , wherein the first gas supply port is provided in an inner wall of the crystal growth chamber. The crystal growth chamber has a guide member provided with an opening through which the drawn crystal can pass,
The first gas supply port is provided on the inner wall of the chamber in a space surrounded by the partition member and the guide member, and has a gas supply path that guides the mixed gas to the melt. 6. A crystal production apparatus for gallate oxide crystals according to 6 .

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